I think you were trying to to a cam shake effect or something when he punched?

kinda jarring and doesn’t let the animation flow right

focus on moving all of the body every frame, or at least most of the body

rarely in real life does anyone move ONE limb

raising an arm, for example, your other arm will move to keep balance, you’ll lean back slightly, etc, it’s no so robotic

you have one frame at the end of the punch where nothing moves except his lower legs, and it’s just not smooth at all

and easing
can never have enough easing